1 /* 2 * Copyright 2018 Google, Inc. 3 * 4 * This is part of HarfBuzz, a text shaping library. 5 * 6 * Permission is hereby granted, without written agreement and without 7 * license or royalty fees, to use, copy, modify, and distribute this 8 * software and its documentation for any purpose, provided that the 9 * above copyright notice and the following two paragraphs appear in 10 * all copies of this software. 11 * 12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR 13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN 15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 16 * DAMAGE. 17 * 18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, 19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO 22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 23 * 24 * Google Author(s): Garret Rieger, Roderick Sheeter 25 */ 26 27 #include "hb-subset-plan.hh" 28 #include "hb-map.hh" 29 #include "hb-set.hh" 30 31 #include "hb-ot-cmap-table.hh" 32 #include "hb-ot-glyf-table.hh" 33 #include "hb-ot-cff1-table.hh" 34 35 static void 36 _add_gid_and_children (const OT::glyf::accelerator_t &glyf, 37 hb_codepoint_t gid, 38 hb_set_t *gids_to_retain) 39 { 40 if (hb_set_has (gids_to_retain, gid)) 41 // Already visited this gid, ignore. 42 return; 43 44 hb_set_add (gids_to_retain, gid); 45 46 OT::glyf::CompositeGlyphHeader::Iterator composite; 47 if (glyf.get_composite (gid, &composite)) 48 { 49 do 50 { 51 _add_gid_and_children (glyf, (hb_codepoint_t) composite.current->glyphIndex, gids_to_retain); 52 } while (composite.move_to_next()); 53 } 54 } 55 56 static void 57 _add_cff_seac_components (const OT::cff1::accelerator_t &cff, 58 hb_codepoint_t gid, 59 hb_set_t *gids_to_retain) 60 { 61 hb_codepoint_t base_gid, accent_gid; 62 if (cff.get_seac_components (gid, &base_gid, &accent_gid)) 63 { 64 hb_set_add (gids_to_retain, base_gid); 65 hb_set_add (gids_to_retain, accent_gid); 66 } 67 } 68 69 static void 70 _gsub_closure (hb_face_t *face, hb_set_t *gids_to_retain) 71 { 72 hb_set_t lookup_indices; 73 hb_ot_layout_collect_lookups (face, 74 HB_OT_TAG_GSUB, 75 nullptr, 76 nullptr, 77 nullptr, 78 &lookup_indices); 79 hb_ot_layout_lookups_substitute_closure (face, 80 &lookup_indices, 81 gids_to_retain); 82 } 83 84 static void 85 _remove_invalid_gids (hb_set_t *glyphs, 86 unsigned int num_glyphs) 87 { 88 hb_codepoint_t gid = HB_SET_VALUE_INVALID; 89 while (glyphs->next (&gid)) 90 { 91 if (gid >= num_glyphs) 92 glyphs->del (gid); 93 } 94 } 95 96 static hb_set_t * 97 _populate_gids_to_retain (hb_face_t *face, 98 const hb_set_t *unicodes, 99 bool close_over_gsub, 100 hb_set_t *unicodes_to_retain, 101 hb_map_t *codepoint_to_glyph, 102 hb_vector_t<hb_codepoint_t> *glyphs) 103 { 104 OT::cmap::accelerator_t cmap; 105 OT::glyf::accelerator_t glyf; 106 OT::cff1::accelerator_t cff; 107 cmap.init (face); 108 glyf.init (face); 109 cff.init (face); 110 111 hb_set_t *initial_gids_to_retain = hb_set_create (); 112 initial_gids_to_retain->add (0); // Not-def 113 114 hb_codepoint_t cp = HB_SET_VALUE_INVALID; 115 while (unicodes->next (&cp)) 116 { 117 hb_codepoint_t gid; 118 if (!cmap.get_nominal_glyph (cp, &gid)) 119 { 120 DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp); 121 continue; 122 } 123 unicodes_to_retain->add (cp); 124 codepoint_to_glyph->set (cp, gid); 125 initial_gids_to_retain->add (gid); 126 } 127 128 if (close_over_gsub) 129 // Add all glyphs needed for GSUB substitutions. 130 _gsub_closure (face, initial_gids_to_retain); 131 132 // Populate a full set of glyphs to retain by adding all referenced 133 // composite glyphs. 134 hb_codepoint_t gid = HB_SET_VALUE_INVALID; 135 hb_set_t *all_gids_to_retain = hb_set_create (); 136 while (initial_gids_to_retain->next (&gid)) 137 { 138 _add_gid_and_children (glyf, gid, all_gids_to_retain); 139 if (cff.is_valid ()) 140 _add_cff_seac_components (cff, gid, all_gids_to_retain); 141 } 142 hb_set_destroy (initial_gids_to_retain); 143 144 _remove_invalid_gids (all_gids_to_retain, face->get_num_glyphs ()); 145 146 glyphs->alloc (all_gids_to_retain->get_population ()); 147 gid = HB_SET_VALUE_INVALID; 148 while (all_gids_to_retain->next (&gid)) 149 glyphs->push (gid); 150 151 cff.fini (); 152 glyf.fini (); 153 cmap.fini (); 154 155 return all_gids_to_retain; 156 } 157 158 static void 159 _create_old_gid_to_new_gid_map (const hb_vector_t<hb_codepoint_t> &glyphs, 160 hb_map_t *glyph_map) 161 { 162 for (unsigned int i = 0; i < glyphs.len; i++) { 163 glyph_map->set (glyphs[i], i); 164 } 165 } 166 167 /** 168 * hb_subset_plan_create: 169 * Computes a plan for subsetting the supplied face according 170 * to a provided input. The plan describes 171 * which tables and glyphs should be retained. 172 * 173 * Return value: New subset plan. 174 * 175 * Since: 1.7.5 176 **/ 177 hb_subset_plan_t * 178 hb_subset_plan_create (hb_face_t *face, 179 hb_subset_input_t *input) 180 { 181 hb_subset_plan_t *plan = hb_object_create<hb_subset_plan_t> (); 182 183 plan->drop_hints = input->drop_hints; 184 plan->drop_layout = input->drop_layout; 185 plan->desubroutinize = input->desubroutinize; 186 plan->unicodes = hb_set_create(); 187 plan->glyphs.init(); 188 plan->source = hb_face_reference (face); 189 plan->dest = hb_face_builder_create (); 190 plan->codepoint_to_glyph = hb_map_create(); 191 plan->glyph_map = hb_map_create(); 192 plan->glyphset = _populate_gids_to_retain (face, 193 input->unicodes, 194 !plan->drop_layout, 195 plan->unicodes, 196 plan->codepoint_to_glyph, 197 &plan->glyphs); 198 _create_old_gid_to_new_gid_map (plan->glyphs, 199 plan->glyph_map); 200 201 return plan; 202 } 203 204 /** 205 * hb_subset_plan_destroy: 206 * 207 * Since: 1.7.5 208 **/ 209 void 210 hb_subset_plan_destroy (hb_subset_plan_t *plan) 211 { 212 if (!hb_object_destroy (plan)) return; 213 214 hb_set_destroy (plan->unicodes); 215 plan->glyphs.fini (); 216 hb_face_destroy (plan->source); 217 hb_face_destroy (plan->dest); 218 hb_map_destroy (plan->codepoint_to_glyph); 219 hb_map_destroy (plan->glyph_map); 220 hb_set_destroy (plan->glyphset); 221 222 free (plan); 223 } 224